#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>
#include <assert.h>

char* my_strncat(char* dest, const char* src, size_t num)
{
	assert(dest && src);
	char* ret = dest;
	while (*dest)
	{
		dest++;
	}
	while ((*src != '\0') && (num != 0))
	{
		*dest++ = *src++;
		num--;
	}
	*dest = '\0';
	return ret;
}

int main()
{
	char arr1[20] = "hello ";
	char arr2[] = "bit";
	my_strncat(arr1, arr2, 4);
	printf("%s", arr1);
	return 0;
}